How the Montgomery Central Appraisal District Appraises Residential Property The following presentation is provided to educate Montgomery County residential property owners about the Analysis & Valuation Phase of the appraisal year. Information will be provided about the mass appraisal process utilized to value residential property. The application of ratio studies and other common statistical measures used throughout the valuation process will also be explained. An overview of market areas/ neighborhoods and their importance on value will also be covered, followed by a brief demonstration of the method applied during the mass appraisal process. Mass appraisal is the systematic appraisal of groups of properties as of a given date using standardized procedures and statistical testing. Appraisal districts use of mass appraisal evolved out of the need to appraise many properties efficiently and equitably each year. The Texas Property Tax Code requires appraisal districts to maintain property records and assign yearly value to all property within each county. Mass appraisal provides appraisal districts the ability to accomplish such a large task in a proficient and unbiased manner. The primary tool used to measure mass appraisal performance is the ratio study. This analysis compares appraised values to market values. Market values are usually represented by individual transactions or sales prices. Each year, the appraisal district must research sales it is able to acquire and apply them in the mass appraisal process to value all property regardless of whether it sold or not. The ratios in a ratio study are referred to as appraisal-to-sale ratios. They are formed by dividing the district s calculated appraised values by the sale price of the same property. For example, a property valued by the appraisal district for $100,000 that sold for $105,000 has a ratio of 0.95 or 95 percent. Appraisal districts are expected to achieve a median ratio level of 100 percent of market value. Texas Property Tax Code section 5.10 also directs the state comptroller to conduct similar biannual ratio studies to ensure appraisal districts are achieving ratios within required parameters. After the July 25th value certification date for appraisal districts, the comptroller s office collects all of that tax year s sale and appraisal data from each district. The Property Tax Assistance Division then begins its own ratio study process to re-check values established by each appraisal district as compared to the sales collected. The Property Tax Assistance Division is required to report if districts are appraising by the State required level and uniformity. Results of the biannual studies may be viewed on the comptroller s website: www.window.state.tx.us
Ratio studies performed by appraisal districts and the comptroller measure two primary aspects of mass appraisal accuracy: level and uniformity. The level of appraisal shows whether the district has appraised typical properties at 100 percent of the legally required level. In Texas, that is the market value or sale price. The uniformity of appraisal indicates how much the percentage of market value varies from the required level within groups of properties. Two of the most common statistical measures used to test appraisal level and uniformity in the mass appraisal process are the median and the coefficient of dispersion. The median is the midpoint, or middle ratio, when the ratios are arrayed in an ascending or descending order. The median separates the ratios into two equal groups, so half of the array is higher than the median and the other half is lower. The median is also the base from which the coefficient of dispersion is calculated. The COD measures how tightly or loosely the individual sample ratios are clustered around the median. A high COD indicates high variation which means few ratios are close to the median and there is low appraisal uniformity. A low COD indicates that there is low variation and the ratios are clustered tightly around the median which translates to high appraisal uniformity. A COD on residential properties below 20.0 is acceptable according to IAAO Standards. As illustrated, the COD is calculated by first finding out the absolute deviation from the median each ratio has. Then, the Average Absolute deviation of the ratio group is determined, divided by the median, and then multiplied by 100 to convert the ratio to a percentage.
ACCT App Ratio Median Absolute Deviation from Median 1 2 3 4 5 91.93% 92.84% 92.62% 92.84% 92.84% 92.84% 93.56% 92.84% 93.80% 92.84% 0.0091 0.0022 0.0000 0.0072 0.0096 0.0282 Total Deviation 5 Divided by # of instances Average Absolute 0.0056 Deviation 0.9284 Divided by the median 0.0061 Equals COD x100 Multiply by 100 to get % 0.6078 COD Accurate identification of market areas is a vital component in the development and utilization of an efficient and accurate mass appraisal system. A variety of forces influences property values. It is the appraiser s responsibility to identify groups of property that experience similar influences and define them as market areas. In Montgomery County market areas are delineated primarily on school district boundary lines. Being said schools districts may be parsed into smaller market areas based on influencing factors. One such example is the Woodlands. Although the Woodlands is in Conroe ISD it is delineated into its own market area. Within these market areas properties are further delineated into neighborhoods. Research on value influences in Montgomery County has resulted in neighborhood delineation by geographic location, age or quality of a structure, by various builders or model types, or other major influencing factors. Appraisers assign numerical descriptors known as neighborhood codes to all property within identified areas of similar value influences. As illustrated, a subdivision may contain various neighborhood codes as a result of the varying identified value influences. The assigning of neighborhood codes allows appraisers to efficiently and uniformly appraise all property in the defined group by the available known sales information.
Appraisers utilize software that enables rapid identification of known sales information, and other pertinent property data within a requested neighborhood code. Texas is one of a few non-disclosure states which means that property transaction sale prices are not available to the public. Due to this, the appraisal district may only rely on sale information provided from owners who respond to sale questionnaires sent by the district, or other forms of sale information willingly provided by owners, realtors, or brokers. In Table 1, information for five known sales was found for neighborhood code Examp#1. The Montgomery Central Appraisal District weighs the number of confirmed sales prices against the total number of improved residential properties in a given neighborhood. If the number of sales is a fairly small percentage of the total number of improved properties the District may decide that there is not enough information to determine whether all properties in that neighborhood should be adjusted. The District also looks at the historical number of sales within a given neighborhood. If the neighborhood is one in which the District receives very few sales then the District may adjust values on a very small percentage of sales. Also neighborhoods with minimal sales information may be compared with comparable neighborhoods to determine if those neighborhoods should be adjusted. ACCT NBHD NBH% LA EFFYR CLS MKTLND MKTIMP MKTTOT CLSDTE SP 1 Examp#1 150 2468 1999 6- $33,660 $174,100 $207,760 2/5/10 $226,000 2 Examp#1 150 2297 1999 6- $32,250 $193,810 $226,060 4/15/10 $241,000 3 Examp#1 150 2616 1999 6- $31,140 $206,930 $238,070 4/21/10 $257,050 4 Examp#1 150 2381 1999 6- $32,360 $179,320 $211,680 4/29/10 $228,000 5 Examp#1 150 2366 1999 6- $32,570 $179,820 $212,390 11/30/10 $227,000 Table 1
Once the available sale and property information is displayed, an appraiser may begin mass appraisal through a process of applying market modifiers to the properties in each defined neighborhood code. Market modifiers are also referred to as neighborhood factors. Factors are used to trend the components of a property s improvement value up or down as a result of the sales provided. A property record card illustrates how improvement components, as identified through prior property inspection, make up the total improvement value. The neighborhood factor is the final valuation step used each year to modify the improvement value up or down so that when added to the land value, a final value is calculated that produces an acceptable appraisal to sale ratio as previously described. Table 2 shows that the prior year neighborhood factor of 150 is producing appraised values lower than the known sale prices. The ratio column is indicating the majority of the sales ratios are below the state required level. Further confirmation is provided by the median ratio of 92.84. The low COD of 0.61 reveals that there is a high level of uniformity in the valuation which means the ratios are closely grouped around the median. An appraiser will begin to adjust the new neighborhood factor to bring the median ratio up closer to the state required level. In this case, a new neighborhood factor of 159 produces an acceptable median ratio of 97.56 and a COD of 0.60 as shown in Table 3. ACCT NBHD NBH% LA EFFYR CLS Land Imp Appraised Value CLSDTE SP App Ratio 1 Examp#1 150 2468 1999 6- $33,660 $174,100 $207,760 2/5/10 $226,000 91.93% 2 Examp#1 150 2297 1999 6- $32,250 $193,810 $226,060 4/15/10 $241,000 93.80% 3 Examp#1 150 2616 1999 6- $31,140 $206,930 $238,070 4/21/10 $257,050 92.62% 4 Examp#1 150 2381 1999 6- $32,360 $179,320 $211,680 4/29/10 $228,000 92.84% 5 Examp#1 150 2366 1999 6- $32,570 $179,820 $212,390 11/30/10 $227,000 93.56% Examp#1 Median 92.84% COD 0.61% Table 2 ACCT NBHD IMP ADJ % YR BLT IMP SF CLS Land Imp Appraised Value CLSDTE SP App Ratio 1 Examp#1 159 1999 2468 6- $33,660 $184,560 $218,220 2/5/10 $226,000 96.56% 2 Examp#1 159 1999 2297 6- $32,250 $204,830 $237,080 4/15/10 $241,000 98.37% 3 Examp#1 159 1999 2616 6- $31,140 $218,750 $249,890 4/21/10 $257,050 97.21% 4 Examp#1 159 1999 2381 6- $32,360 $190,070 $222,430 4/29/10 $228,000 97.56% 5 Examp#1 159 1999 2366 6- $32,570 $190,630 $223,200 11/30/10 $227,000 98.33% 5 Examp#1 Median 97.56% COD 0.60% Table 3
The Appraisal District is responsible for appraising properties at market value as of January 1 st of each tax year. To accomplish this task the District collects sales information from transactions that occurred during the twelve months preceding the appraisal date. It has been the District s policy for many years to consider foreclosure or distressed transactions. These transactions are analyzed to determine if they are representative of or affecting the market in each neighborhood. This process is repeated annually for approximately 3,000 neighborhood codes to reflect the changing real estate market and value approximately 176,000 residential properties in the county. We hope this presentation provided a better understanding of the process used to value residential properties by explaining the following important elements: Mass appraisal..ratio studies.statistical measures.market areas.and Neighborhoods. A demonstration of a tool utilized during valuation was also provided to further illustrate how the State required accuracy and uniformity is achieved. Thank you for your interest in the appraisal process.